An Iranian cartoonist has been sentenced to 25 lashes for a caricature of a local MP, the semi-official Ilna news agency has reported.

Ahmad Lotfi Ashtiani, MP for Arak, took offence to a cartoon published in Nameye Amir, a city newspaper in Arak.

The cartoonist, Mahmoud Shokraye, depicted Ashtiani in a football stadium, dressed as a footballer, with a congratulatory letter in one hand and his foot resting on the ball.

Iranian politicians, including Ashtiani, have been recently criticised for interferring in the country's sports. The MP's forehead in the cartoon (as also in reality) has a dark mark, said to be the sign of a pious muslim, caused (supposedly) by frequent prostration during prayer.

Shokraye was subsequently sued by the MP for having insulted him. A court in Markazi province, of which Arak is the capital, sentenced the cartoonist to 25 lashes – an unprecedented punishment for an Iranian cartoonist.

His sentence has triggered outcry among Iran's online community with many calling on cartoonists to draw new caricatures of the MP. Many have expressed their anger on Twitter and Facebook.

Speaking to the Guardian, Nikahang Kowsar, a prominent Iranian cartoonist who fell foul of the Iranian regime after famously caricaturing a prominent cleric like a crocodile in a series of cartoons, said: "This verdict is a direct threat to each and every cartoonist working inside Iran. From now on, if this sentence is not set aside, any public official could sue the cartoonists for portraying him/her in a cartoon."

Kowsar, a member of the board of Cartoonists Rights Network International, has also participated in the campaign of drawing Ashtiani's cartoon. "In the past, cartoonists were prohibited from drawing clerics, but from now on, non-clerics have joined the league of the 'sacred cow'," he said.

"Right now, a number of Iranian cartoonists have had to leave the country in fear of imprisonment, and the rest have either quit the business, or are censoring themselves to avoid persecution and imprisonment." Kowsar currently lived in the United States. Another Iranian cartoonist, Mana Neyestani, who was also the victim of state's aggression towards cartoonists in Iran, has also drawn a cartoon of Ashtiani.

Iranian journalist Masih Alinejad said Shokraye's sentence was due to Iranian authorities' lack of tolerance towards any form of criticism – in cartoons, newspaper articles and the arts.

"His cartoon has absolutely no problem, he has drawn the MP exactly the way he is, even with his prayer mark," she said. "Actually the MP's cartoon looks better than the MP himself."